In a process of transporting a strip-shaped optical film F, the optical film F is cut to a predetermined length. The first feedback circuit outputs, of an output voltage, a voltage according to a magnitude of a low-frequency component that is not greater than or equal to a predefined first cut-off frequency. In one approach a design data file that contains fabrication process information and reticle information is processed using design rules to obtain a design map with a spatially varying overlay error budget that defines a localized tolerance to overlay errors for different spatial locations on the design map. A difference in potential between the first electrode plate and the second electrode plate is measured. An end of the transverse leaf spring is coupled in an articulated manner with the suspension arm and spaced apart from a wheel-side end of the suspension arm. More specifically, embodiments of the present disclosure are directed to an attachment unit that is configured to be inserted and removed from a housing of a consumer product.